The 250W model is road legal and can be used on public roads without needing a licence or registration. The 750W model is not a road legal bike and can be used for off-road or in private property. Here is a quick comparision between the specifications of 250W and 750W motors:
750W
40 km / h
(max speed)
- 85 NM of torque
- Can be limited to 500W or 250W via the setting menu
250W
25 km / h
(max speed)
- 55 NM of torque